A Case of Reactive Arthritis Secondary to Coronavirus Disease 2019 Infection.

To the Editor:

A 47-year-old Indian man from Chennai working in Singapore in construction presented with a 3-day history of progressive right knee pain and swelling, and pain at his glans penis. Three days prior, he had a low-grade fever lasting for 1 day. He reported his wife as his only sexual partner. On examination, his right knee was tender with a large effusion (Fig. A). Mild erythema and swelling of his glans penis was noted.

A, Photograph showing a large right knee effusion. Arrow pointing to right knee effusion. B, Radiograph of the right knee showing right suprapatellar effusion with mild osteoarthritic changes. Arrow pointing to suprapatellar effusion and arrowhead pointing to joint space narrowing. Color online-figure is available at http://www.jclinrheum.com.

Nasopharyngeal and throat swab by real-time reverse transcription-polymerase chain reaction (PCR) confirmed that patient was positive for SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2). This was done as he had exposure to coronavirus disease 2019 (COVID-19) cases 1 week earlier. Test results for human immunodeficiency virus, syphilis, chlamydia, and gonorrhea were negative. Anteroposterior radiograph of the right knee revealed a right suprapatellar effusion with mild osteoarthritic changes (Fig. B).

Bedside diagnostic joint aspiration drew 120 mL of turbid yellow fluid, for which no crystals were seen. Synovial Gram stain, gonococcal, bacteria cultures, and gonococcal and chlamydia PCR were negative. Synovial fluid PCR and viral cultures for SARS-CoV-2 were also negative.

A diagnosis of reactive arthritis secondary to COVID-19 infection was made. He was treated with etoricoxib and administered intra-articular triamcinolone into the knee joint 1 week later when the effusion recurred.

To date, there have been no published reports in the literature of reactive arthritis secondary to COVID-19 infection. The timing of disease onset is consistent with COVID-19 infection as a likely trigger. The high CT value of his COVID-19 swab on admission indicated low copies of viral RNA. This would suggest that the patient was late in the course of COVID-19 when he developed arthritis and balanitis,[1] with no other clear identifiable sources of infection. Nevertheless, more observations will be required to determine if COVID-19 is indeed associated with reactive arthritis.